The invention relates to an illumination apparatus having at least a first and a second illumination unit, wherein each of the illumination units comprises an LED arrangement and a supply device for supplying the LED arrangement, each of the LED arrangements comprising at least one LED group having a multiplicity of LEDs and the LED groups of the LED arrangements being similar, and having a control device for driving the at least two illumination units with a common nominal dim drive value, the nominal dim drive value driving the illumination units in such a way that the similar LED groups of the illumination units are operated in a dim mode. The invention also relates to a method for operating the illumination apparatus in the dim mode.